Lathe drive mechanism



' Junezs, 1942. H H, LOGAN f 2,287,046

LATHE DRIVE MEGHANISM Filed March 15, 1941 sheets-sheet 1 az 7.9 a? \1 /l/ nl June 23, 1942. H. H. LOGN 2,287,046

LATHE DRIVE ME-CHANISM Filed March l5, 1941 4 Sheets-Sheet 2 f5@ l 52 /7 [11., K y I i fr Z i :i:

l i l. /.7v3 y i I l I I f4 l l /f-N i i I l l Il E /5 c 74/ i l June 23, H H LOGAN LATHE DRIVE MECHANISM Filed MarOh 13, 1941 4 Sheets-Sheet 3 June 23, H LOGAN LATHE DRIVE MECHANISM Filed March 15, 1941 '4 sheets-sheet 4 Patented June 23, 1942 paire-D STAT i3 rr OFFICE LATHE DRIVE MECHANISM 'Henry H. Logan, Chicago, Ill., assignorto Logan Engineering Co., Chicago,lll., a; corporation of Illinois Application March 13, 1941, Serial No. 383,070

(Cl. 'Mi-217) 13 Claims.

Small motorrdrivenA machines such as lathes, A

shapers, milling machines, and the like, are now being used in large and rapidly increasing numbers, .both by industry, and by individuals in work shopsV located in the individuals homes.

The provision of suitable motor drives for such machinesv has in the pastpresented a diiiicult" problem, due to the factthatvthe vmotor drives -usually employedfordriving such smaller machines have caused vibration tobeset up in the driven machines which adversely affected the work performed .by such machines.

The small inexpensive.motorsfrequently selectedfor driving vmachines Vofthis class are usually not balanced tothe same degree as .more

`expensive motors, with the, result that the vmotors are apt to vibrate. n4Since the motors are relatively heavy in proportion to they weight of the driven machines such vibrations are transmitted to the driven machines when employing customary types of motor drive. arrangements.

Most machines of theclass referredto Aare providedfwith a changeV speed arrangement consisting of a pair of step or cone pulleys, one of which -is secured to the spindle ofthe driven machinefand the other vof which issecured to a countershaft, so that. a change in driving ratio may be accomplishedby the shifting of abelt on the cone pulleys. ,Sincethe operatorsof these machinesare frequently not highly skilled, the

shifting of the belt, in `its normaldriving condition of tautness, involves some .danger to the operator, and frequently causesabrasion of lthe edges of the belt. VByloosening the drive belt `on the cone pulleys before attempting to shift the belt, the danger to the operator, and abrasion of the belt would be greatly reduced. VSuch loosening of the belt in the case of drive mechanisms heretofore used has usually been considered impractical, since in .the first place no ready .means for loosening the belt. has been provided, and in the second place it isdifcult to restore the .belt to its properv driving tension.

nism is associated,.and tohave principal support independentlyY of the driven. machine.

Anotherobject is .to drive -a small Vlathe ,or

the like Yby means of a cushioned drive mechanism attached tothe lathe, and independently supported with respect tosaid lathe.

vAnother object is to provide a` motor drive Ymechanism with a three Vpoint support, two

mechanism vvith` a weighted closure member interconnected with .a .belt tautening portion of said belt drive mechanism, to tauten a driving belt by the .weight of said closure. member.

Another object is to mount a lathe drive Amechanism on. a lathe, with a .major portion of the weight of .said drivemechanism independently supported with. respect to said lathe, and having balanced Adrive connection With said lathe to prevent distorting strain on the lathe.

Other objects and advantages of the invention will be. apparent from the following description and. the accompanying ldrawings invwhich vsimilar characters of reference -indicate similarparts throughout the several views.

Referring to the drawings, ofwhich `there are four sheets,

Fig. l is a view in end elevation` of a;.1athe having a driveunit embodying the present invention, portions thereof being broken away to show the interior construction; I

Fig. 2 is a fragmentary rear elevational v-iew of the 4lathe and associated drive mechanism illustrated in Fig. `v1, the left hand end of the lathe as illustrated, being broken away;

Fig. 3 is an enlarged fragmentary sectional view taken on the offset .planes of the broken line 3-.-3 of Fig. l, the lathe headstock 'being broken away; l

Fig. 4 is a vertical fragmentary sectional vie of the upper portion 'only of the lathe drive mechanism taken on the plane of the lined- 4 of Fig. 3;

Fig. 5 is an enlarged fragmentary sectional view of a modified type of mounting pintle, the section being similar to that of Eig. 3; and,

Fig. 6 is a View in end elevation of a bench lathe .mounted on a bench and having a modiiied, type of drive mechanism, the. lower portion of the .bench being brokenV away.

Referring to the embodiment illustrated in supporting legs l2, chippan I3, and headstock I4. A conventional gear cover I5, used to cover the lead-screw drive gears, not illustrated, is mounted on a conventional hinge I6. The top of the housing of the headstock is open as best illustrated in Fig. 3, and is adapted to be closed by a cover I1, which is hinged at its rear end, to the head frame I8 of a lathe drive mechanism generally indicated by the numeral 29.

The head frame member I8 is attached to the lathe II by means of a pair of pintles 2| and 22, which are secured in bosses 23 and 24 respectively, projecting inwardly from the sides of the head frame I8. The pintles are secured in position as by means of set screws 25. Each of the pintles is provided with a rubber bushing 26, the rubber bushings being in turn mounted in openings in a pair of brackets 21 secured to the rear of the housing of the lathe headstock I4 by machine screws 28.

The housing of the headstock I4 is notched out as at 29, see Figs. 3 and 4, to provide clearance for a drive belt 39 which is driven by a cone pulley 3| secured to a countershaft 32. The countershaft 32 is journaled in bearings 33 and 34 carried by a yoke 35 which comprises part of an automatic belt tension control.r

'I'he yoke 35 is arranged to swing the cone pulley 3I toward a similar cone pulley, not illustrated, carried on the lathe spindle in a conventional manner, so as to loosen the belt 39 when the cover I1 is raised to the open or dotted line position illustrated in Fig. 4, and to tauten the belt when the cover I1 is moved to the closed solid line position illustrated in Fig. 4.

The yoke 35 is pivotally mounted on a rod 36 which is carried in brackets 31 projecting downwardly from the head frame I8, see Figs. 4 and 6. The countershaft 32 is journaledin bearings 38 and 39, as illustrated in Fig. 3, the bearings being secured between oppositely disposed set screws dlland 4I, which are threaded through bosses 42 and 43 at the upper end of each of the forked side portions o-f the yoke 35. Each of the set screws 49 and 4I is provided with a lock nut 46 The countershaft 32 is retained against longitudinal movement in the bearings 33 and 34 by collars 44 and 45 which are secured to the countershaft 32 inside of each of the bearings 33 and 34 respectively.

The yoke 35 has an integral rearwardly projecting arm 41, which is positioned beneath a pin 48 slidably mounted in a boss 49 of the head frame I 8. The pin 48 may have a longitudinal key-way 50 extending slightly less than the full length of the pin 48y a stud 5I being threaded into the boss 49 to have a reduced nose portion of said stud riding in the key-way 59 to limit the sliding movement of the pin 48.

A belt tension adjusting screw 52 is threaded through a boss 53 in the cover I1, see Fig. 3, so that when the cover is in the closed position shown in'solid lines in Fig. 4, the screw 52 forces the sliding pin 48 downwardly, thereby exerting a downward pressure on the rearward or free end of the arm 41. This action pivotally urges the yoke 35 in a counter-clockwise direction, as from the dotted to the solid line position of Fig. 4, and thereby exerts a tautening inuence on the belt 30.

When the cover is raised to the dotted line position of Fig. 4, the Vsliding pin 48 is released by the screw 52, whereupon the yoke 35 is free for clockwise pivotal movement as to the dotted line position of Fig. 4, to relieve the tension on the belt 39. When the tension on the belt 30 is thus relieved, the shifting of the belt on the cone pulleys may be easily and safely performed without danger t0 the operator or damage to the belt.

A self-latching cover link 54 is pivoted at 55 to the side of the head frame I8, and is provided with a slot 55 in which a stud 56, secured to the cover I1, is adapted to ride. I In the closed position of the cover I1, the stud 56 is at the inward end of the slot 55, and when the cover is moved to the open, dotted line, position of Fig. 4, the stud 56 moves outwardly in the slot 55. When the'stud 56 reaches the outer end of the slot 55, the weight of the link 54 moves the link downwardly to bring the stud 56 into the angularly offset outer end portion 51 of the slot 55 to latch the cover in the raised position. The link 54 may be released for lowering the cover by manually moving the link upwardly to again bring the stud 56 into the main straight portion of the slot 55. A pair of rubberpads 9| are mounted to project below the lower edge of the cover I1, see Fig. 5, to rest on the upper edge of the housing of the headstock I4 to form a resilient support for the front edge of the cover.

A belt driven pulley 58 is secured to the outer end of the countershaft 32, as illustrated in Fig. 4, by means of a set screw 59, the pulley 58 being driven as by means of a belt 68 from an electric motor 6I.

The motor 6I is mounted on a motor support bracket 62 which is pivotally connected as at 63 to a support frame64. The support frame 64 is secured to the head frame I8 as by means of bolts 65 and 66, see Fig. 4, the support frame 64 being preferably of cast iron so as to have suflicient mass and rigidity to absorb minor vibrations which might otherwise be set up by the action of the motor and belts.

The motor support bracketV 62 is formed with an upwardly extending adjusting arm 61, see Fig. 1, which is provided with an opening to receive a bolt 68. The bolt 68 extends through the wall of the support frame 64 and is provided with a plurality of nuts 69, 19, 1I and 12 by means of which the position of the motor support bracket 62 can be pivotally adjusted to regulate the tension on the belt 60.

A sheet metal belt shield 13 is hinged as at 14 to the support frame 64 to provide a safety enclosure for the belt 60 and associated parts.

The lower end of the support frame 64 is curved inwardly as at 15, andV is provided with a vertically extending opening 16 located approximately beneath the center of gravity of the drive mechanism 20. A tubular supporting leg 11 is secured in adjusted position in the opening 16 as by means of set screws 18. The lower end of the tubular support 11 is provided with a resilient rubber cap 1.9 to absorb minor vibrations, and to prevent transmitting vibrations to a supporting iioor 80.

A ground wire 8| may be secured to the supporting leg 11 and to the leg I2 of the lathe. The leg I2 is in turn electrically connected to a suitable ground indicated diagrammatically at 82 in order to ground any static charge or any current which might be conducted to the lathe or drive frame as by means of a possible short circuit.

In Fig. 5 is illustrated a modified pintle construction for connecting the lathe drive mechanism to the headstock. VIn the construction illustrated in Fig. 5, the housing of the headstock I4 is provided with brackets 21 similar to those illustrated-in Fig. 3and withthe' same type' of rubber bushings 26 inserted' in theopenings in the bracket's2l.V Thehead frame I8 is formed with inwardlyextendingbosses and-84. The bosses 8f3! and i811l have4 internally threaded" openings into which are screwed pintle bolts 86 and' 81, respectively. Therpintle bolts have unthreaded inner ends 38 ofY reduced diameter to enter the rubber bushings 26.

A modified type of drive mechanism is illustrated in Fig. 6. Thisdrive mechanism is particularly adaptedfor the driving of bench lathes of the type indicated'generally by the numeral @-9, the lathe being illustrated as mounted upon a bench 85'.

Since the lathe itself, except for the absence of the chip pan and legs, and the entire head frame i8' andy its parts are substantially the same as those illustrated in Figs. 1 to 4, inclusive, it will be unnecessary to again describe the lathe and the vupper parts of the drive mechanism in detail. These parts in Fig. 6 are therefore given the same numbers as the corresponding parts in the illustrations of Figs. 1 to 4, inclusive.

A lower support frame 90 has a divided upper end consisting of arms 9| and 92 which are provided with openings positioned to register with the openings in the head frame I8 to receive bolts 93 which secure the support frame 90 tothe head frame I8.

A motor support bracket 9G is pivoted between a pair of arms 95 extending rearwardly from the lower portion of Athe support frame 90. The bracket S4 is retained in pivotal adjustment by means of a bolt 96 which is inserted through an opening in an upwardly extending arm 91 integral with the bracket 94, the bolt 55 also extending through a transverse web portion 9B of the support frame $0. Pivotal adjustment of the bracket 94 is accomplished by means of nuts 99, |60, IOI and |02 threaded onto the bolt 96 as illustrated.

A motor |03 is bolted to the support bracket 95 and is arranged to drive a belt which may be considered as being the same belt 50 as that illustrated in Figs. 1 to 4, inclusive. A sheet metal belt guard |04 is mounted on hinges |05 and |00 carried by a bracket |01 which issecured to the support frame 90.

A threaded support leg |08 is screwed into the base of the frame 90 at the-approximate center thereof, and is locked in adjusted position by means of a lock' nut |09. A rubber cap IIO forms a cushioned support for the leg |08 andacts to absorb minor vibrations which otherwise might i be transferred to the bench 85.

If desired, the type of drive unit illustrated in Fig. 6 may be used in the manner of the drive unit illustrated in Figs. 1 to 4, inclusive, by substituting for the leg |08 a leg suiiiciently long. to extend entirely to 4the oor. When thus used, the modified mechanism illustrated in Fig. 6 may be used where a less expensive drive mechanism than that illustrated in Figs. 1 to 4, inclusive, is

desired, and at the same time secure` the advan- TheV present drive 'mechanism provides asimple, safe: positivedrive fora small lathe ormachine" tool andonewhich is readily adapted for attachment to practically any such machine. TheV safety' features including the automatic belt tensioncontrol give automaticprotection to the operatorfduri'nga belt-,shifting operation or other operation which requires'ithe raising of the'cover This featurealsogreatl'y simplifies such belt shifting operation aswell as adding materially to the life of the belt'.

The cushioned weight of the drive-mechanism being mainly carriedby the single leg'insures against any twisting orother strains even when mounted on a rough' or-funeven iloor, while the cushionedv connection to the lathe absorbs any minor vibrations., such as m'otor vibrations, which otherwise might be transmitted to the lathe.

While I have illustrated a preferred embodi-` mentl of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to'be limited to the precisevdetailsof construction as set forth, but desire to avail myself of al1 changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A drivemechanism comprising in combination with a driven machine having a driven pulley thereon, a drive'mechanism frame mounted at a side of said driven machine, a single point support beneath thev frame independent of the driven machine, a countershaft journaled in the frame, a thrust connection'between the frame and the driven machine, a driving pulley mounted on' the countershaft opposite the driven pulley ori-the driven machine, a belt mounted around the' countershaft driving pulley. and the driven pulley on the machine, the two reaches of the belt lying on opposite sides of a horizontal line through the thrust connection, and a driving motor mounted onsaid frame and having driving connection with said countershaft.

2.- A drive mechanism-comprising in combination twith a driven machine having a driven pulley thereon, a frame mounted at. a side ofthe driven machine, a driving .pulley mounted on said frame and spacedlaterally from said driven pulley, a drive belt connecting the driving pulley to the driven pulley on the driven machine, a motor, driving connection between the motor and-the driving pulley, tvvoy point cushioned thrust connection between the driving pulley and the driven machine to hold the drive belt in tension, the thrust connection lying vertically adjacent the median line-of tension of -said drive belt the points of cushioned.connection-being located-on opposite sides of the plane of the belt, and a single leg support mounted beneath said frame and independent-of the driven machine substantially to support the drive mechanism.

3. A drive-mechanism comprising in combination ywith a-driven machine having a driven pulley thereon, a drive mechanism frame, a single point supportl beneath-the frame, apair of laterally spaced thrust connections between the frame and the driven' machine, said connections constituting the' sole thrustconnection between the frame andthe driven machine, ayoke pivotally mounted in the frame, a'pulley journaled on the yoke, al motor mounted on Ythe frame Aand having driving connection with the pulley journaled'in the yoke, a-beltmounted aroundthepulleyjournaled on the yoke and the driven pulley on the driven machine, a cover hinged to the frame to enclose at least partially the pulley journaled on the yoke, and belt tightening means carried by the cover and positioned to engage a yoke element on a closing movement of the cover to move the driven pulley mounted in the yoke to increase the tension on the belt.

4. A drive mechanism comprising in combination with a driven machine having a driven pulley thereon, a drive mechanism frame, a single point support beneath the frame, a movable countershaft support, a countershaft journaled in the support, a pair of cushioned pivot connections between the frame and the driven machine, a driving pulley mounted on the countershaft opposite the driven pulley on the driven machine, a belt mounted around the countershaft driving pulley and the driven pulley on the machine to lie in a vertical plane, located Wholly between the cushioned pivot connections, the countershaft support having a normal position releasing the tension on the belt, a hinged cover mounted to enclose, at least partially, the belt and the driving and driven pulleys, and means connecting the cover and the countershaft support as the cover is moved about its hinge toward closed position to move thev countershaft support to separate the pulleys surrounded by the belt, thereby to increase the tension on said belt.

5. A drive mechanism comprising in combination with a driven machine having a driven pulley thereon, a drive mechanism frame, a single point support beneath the frame, a countershaft support movably mounted in the frame, a countershaft journaled in the countershaft support, a driving pulley mounted on the countershaft opposite the driven pulley on the driven machine, a belt mounted around the countershaft driving pulley and the driven pulley on the machine, a cover of substantial Weight pivotally connected to the frame, and adapted to enclose at least part of the belt and the pulleys around which it is mounted, a belt tightening thrust member adiustably mounted on the cover and positioned operatively to engage the movable countershaft support on a release of the cover to a closed position to move the countershaft supported pulley to an adjusted belt tensioning position.

6. A driving mechanism comprising in combination with a driven machine having a driven pulley thereon, a drive mechanism frame connected to the driven machine to extend laterally from the portion thereof having the driven pulley thereon, a countershaft support movably mounted in the frame, a countershaft carried by the support to be movable toward and away from the driven pulley, a driving pulley mounted on the countershaft opposite the driven pulley on the driven machine, a belt mounted around the countershaft driving pulley and the driven pulley on the machine, a cover of substantial weight pivotally connected to the frame to over-lie at least partially the belt and the pulleys around which it passes, an adjustable thrust member carried by the cover, and thrust responsive means operatively associated with the movable countershaft support, said thrust responsive means being positioned to be engaged by the adjustable thrust member carried by the cover as the cover is moved to closed position, to move the countershaft away from the driven pulley to produce a predetermined increase in tension on said belt.

7, A drive mechanism for a driven machine,

having a frame and a driven pulley thereon. said drive mechanism including a frame, a single point support beneath the frame, a pair of laterally spaced thrust connections between the frame and the driven machine, said connections constituting the sole thrust connection between the drive mechanism frame and the driven machine, a yoke pivotally mounted in the drive mechanism frame, a pulley journaled on the yoke, a motor mounted on the frame and having driving connection with the pulley journaled on the yoke, a belt mounted around the pulley journaled on the yoke and the driven pulley on the driven machine, and belt tightening means mounted to engage a yoke element on a predetermined movement of said belt tightening means to increase the tension on the belt.

8. A drive mechanism comprising in combination with a driven machine having a driven pulley thereon, a drive mechanism frame, a single point support beneath the frame, a movable countershaft support, a countershaft journaled in the support, a thrust connection between the frame and the driven machine, a driving pulley mounted on the countershaft laterally opposite the driven pulley on the driven machine, and movable toward and away from the driven pulley, a belt mounted around the countershaft driving pulley and a driven pulley, the countershaft support having a normal position releasing the tension on the belt, and means mounted to move the countershaft support away from the driven pulley, thereby to increase the tension on said belt.

9. A drive mechanism comprising in combination with a `driven machine having a driven pulley thereon, a drive mechanism frame, a single point support beneath the frame to support substantially the entire weight of said `drive mechanism, a countershaft support pivoted on said frame, a countershaft journaled in said countershaft support eccentrically to the pivot of said countershaft support, a thrust connection between the frame and the driven machine, said thrust connection being substantially free from Weight of the drive mechanism, a motor mounted with its shaft beneath the countershaft and having driving connection with the countershaft, said motor having pivotal connection with the frame laterally from said motor shaft, and means independent of the driving connection between the motor shaft and lthe countershaft to limit the downward displacement of the motor about its pivotal support.

l0. A drive mechanism comprising in combination with a driven machine having a driven pulley thereon, a drive mechanism frame mounted at a side of said driven machine, a support beneath the frame independent of the driven machine, a countershaft journaled in the frame, a thrust connection between the frame and the -driven machine, a driving pulley mounted on the countershaft opposite the driven pulley on the driven machine, a belt mounted around the countershaft driving pull-ey and the driven pulley on the machine, the two reaches of the belt lying on opposite sides of a horizontal line through the thrust connection, and a driving motor mounted on said frame and having driving connection with said countershaft.

11. A drive mechanism comprising in combination with a `driven machine having a driven pulley thereon, a drive mechanism frame, a support beneath the frame, a pair of laterally spaced thrust connections between the frame and the driven machine, said connections constituting the sole thrust connection between the frame and the driven machine, a yoke pivotally mounted in the frame, a pulley journaled on the yoke, a motor mounted on the frame and having `driving connection with the pulley journaled on the yoke, a belt mounted around the pulley journaled on the yoke and the driven pulley on the driven machine, a cover hinged to the frame to enclose at least partially the pulley journaled on the yoke, and belt tightening means carried by the cover and positioned to engage a yoke element on a closing movement of the fcover to move the driven pulley mounted in the yoke to increase the tension on the belt.

12. A drive mechanism comprising in combination with a driven machine having a driven pulley thereon, a ydrive mechanism frame, a support beneath the frame, a movable countershaft support, a countershaft journaled in the support, a pair of cushioned pivot connections bctween the frame and the driven machine, a driving pulley mounted on the countershaft opposite the driven pulley on the driven machine, a belt mounted around the countershaft driving pulley and the driven pulley on the machin-e to lie in a vertical plane, located wholly between the cushioned pivot connections, the countershaft support having a normal position releasing the tension on the belt, a hinged cover mounted to enclose, at least partially, the belt and the driving and driven pulleys, and means connecting the cover and the countershaft support as the cover is moved about its hinge toward closed position to move the countershaft support to separate the pulleys surrounded by the belt, thereby to increase the tension on said belt.

13. A ldrive mechanism comprising in combination with a driven machine having a driven pulley thereon, a drive mechanism frame, a support beneath the frame, a movable countershaft support, a countershaft journaled in the support, a thrust connection between the frame and the driven machine, a Adriving pulley mounted on the countershaft laterally opposite the driven pulley on the driven machine, and movable toward and away from the driven pulley, a belt mounted around the countershaft driving pulley and a driven pulley, 'the countershaft support having 

